The Denro Small Digital Voice Switch is our next generation small switching system targeted to the small tower, facility or mobile ATC environment. The Denro SDVS is identical in user operation to the approved Federal Avi......The Denro Small Digital Voice Switch is our next generation small switching system targeted to the small tower, facility or mobile ATC environment. The Denro SDVS is identical in user operation to the approved Federal Aviation Administration (FAA) version Enhanced Terminal Voice Switch (ETVS). The new switch integrates the compact and reliable features of the proven Small Tower Voice Switch (STVS) product with the state-of-the-art digital design and touch entry operation of the ETVS.